Raspberry Pi Powers Commodore 64 Expansion Cartridge, Plays Doom

Commodore was a big name in the 1970’s, 80’s and early 1990’s. Its range of home computers has spanned decades, but the Commodore 64 shines just a little bit above the rest. Frntc aka Carsten I devised a cartridge powered by a Raspberry Pi. RAD expansion unit, which emulates RAM expansion and provides a CPU boost for 40+ year old machines. And the classic way to test it should be “Does it run Doom?” That’s true, but the Raspberry Pi does most of the heavy lifting. Still, graphics and sound are all thanks to a custom Commodore chip.

The RAD expansion unit connects to a Commodore 64 (or 128) cartridge port and emulates a RAM expansion unit of the time using a Raspberry Pi 3A+, 3B+ or Zero 2 W. It also bypasses the main MOS Technology 6510 / 8500 CPU (running at a mighty 1.923 MHz for NTSC and 0.985 MHz for PAL) to provide the full power of the Raspberry Pi’s Arm CPU. RAD can emulate up to 16MB of RAM. This is many times his original 64KB of RAM on the stock model. This means RAD is giving you the horsepower to play Doom’s tech demos, but you can only see them thanks to the onboard graphics chip VIC-II.